This invention relates to cutting devices and particularly devices for severing continuous lengths of stock material into shorter length pieces. The invention has utility with respect to many materials, but has particular utility with respect to mineral fiber mats or boards and therefore, the invention will hereinafter be described in that environment.
As is known, mats or boards of agglomerated mineral fibers, usually incorporating a binder, are manufactured in continuous processes. For shipment or other subsequent handling, it is necessary to sever or cut the mat transversely of its direction of movement so that sections of mat of predetermined lengths are produced. It should be understood that the mat or board usually is substantially continuous across its width and it is necessary to cut through substantially the entire mat in order to produce acceptable pieces.
Heretofore, cutters of the so-called "flying" type have been utilized for cutting glass fiber mat or board. These cutters move longitudinally in the direction of the travelling mat or board during the cutting operation. This longitudinal movement is necessary because the duration of the cutting operation is relatively long in comparison with the lineal speed of the product being cut, so that problems would occur upstream of the cutting operation if the cutter did not move with the mat. Previously, these flying cutters employed such means as a guillotine type blade for shearing the mat or a saw blade for example, a bandsaw blade, extending transversely of the mat or board for cutting it.
Also, cutting devices employing a number of rotating knives, saws, or separating discs, arranged in a common plane, on a moveable beam or support member, are suitable for cutting continuous length materials in the form of relatively narrow strips. However, with such an arrangement, there is always an area or zone between adjacent cutting elements that is not acted upon by either cutting element. Thus, if such an arrangement were to be utilized to cut material having a substantially constant cross-section through the cutting zone, as for example a mineral fiber mat or board, the cutting operation could not be accomplished by merely advancing the cutting elements in one direction through the mat; it would be necessary also to move them in a direction transverse to the mat in order to sever it completely. This additional transverse movement of the cutting device is disadvantageous because it increases the cost of the device and it increases the duration of the cutting operation.